Method and means for producing ebullition in liquefied petroleum gases



N. M, JONES .l .Tw e e h q v S t e e h W S T; s mi. T;- m Um BS EA GGSAmMw CUl um my. Pm RP@ ODe FEF I MFM AE1 EUi Q MIF ML Am D O H T E MMarch 4, .194?.

N. M. JONES 2,416,924 METHOD AND MEANS FOR PRODUCING EBULLITION INLIQUEFIED PETROLEUM GASES Filed Feb. 27, 1943 3 Sheets-Sheet 2 Zhwentor:Fie/ son Nl. Joh/Es '(1 ttorneg 5 Patented Mar. 4, 41947 METHOD ANDMEANS FOR PBODUCIN G EBULLITION IN LIQUEFIED PETROLEUM casas Nelson M.`Jones, Sarasota, Fla., assignor to Greens Fuel, Incorporated, Sarasota,Fla., a corporation of Florida i Application February 27, 1943, SerialNo. 477,373

This invention relates to a method and means for producing ebullitionand more particularly to the ebullition of liqueed petroleum gases suchas .butane, propane, and the like.

Butane mixtures, such as used for domestic `fuels, have a theoreticalinitial boiling or evaporating point which is around eighteen degreesFahrenheit. At this temperature, the boiling barely starts. In practice,when the temperature of butane falls to approximately thirty-two tothirty-live degrees Fahrenheit, such boiling. or evaporation ceasesbecause the liquid is still. It, however, 'the liquid is properlyagitated by mechanical or other means, the boiling will take place at alower temperature, theoretically down to eighteen degrees Fahrenheit.

Liqueied petroleum gases are widely used in some sections for domesticpurposes. It is a common practice to pipe ,liquefied butane, propane,and the like from a delivery tank into a closed underground tank so thatthe heat of the earth will cause the liquid to boil and form a gas orvapor, which vapor is piped to points of consumption. 'Since liquidbutane, in practice, does not actually boil until a temperature ofaround thirty-two to thirty-five degrees Fahrenheit is reached,operation in cold weather is sometimes troublesome. Even though thetanks are buried beneath the top of the ground, the temperature of theliquid sometimes falls below vthe actual boiling point, and as a resultIno 3 Claims. (Cl. 62-4) permanently changed and therefore such materialsare commonly called ebullators.

It is another object of this invention to provide a catalytic agent of acapillary structure such as rattan, reed, bamboo, or cellular woods withthe natura1 skin thereon, in combination with a supply of liqueedpetroleum gas, which agent is capable of producing an internal pressurediierential underneath the surface of the liquid and thus producebubbles of gas for asitating the main body of the liquid. The use ofrattan, reed. bamboo, and other cellular woods in. this invention ismost effective when employed in the natural form; that is, permittingthe natural skin to remain thereon and being cut in suitable lengthsbetween the joints so that the longitudinal capillary passages willextend from end to end of the lengths. The

' natural skin is necessary to this process because g5 ground tank forcontaining vaporizable liquid petroleum gases such as butane, propane,and the like, or mixtures thereof inf combination with tubular pipes orrecesses communicating with the lower portion of the tank for housingcatalytic agents such as rattan, reed, bamboo, or other cellular woods.The pipes or recesses are heated by the surrounding earth to cause theliquefied petroleum gas and catalytic agents within the pipes orrecesses to also be heated, thereby causing ebullition to be controlledmore directly by the ground temperature than is the case when the agentis submerged in the liquid systems practicable in a wider range oftemperatures.

It is another object of this invention to provide an ebullition systemcomprising a tank having a quantity of liquefied petroleum gas such asbutane, propane, and the like therein, and a catalytic agent such as apiece of longitudinally porous rattan, bamboo, reed, or cellular woods,submerged in the liqueiled petroleum gas to produce boiling at a lowertemperature than the liqueiied gases would otherwise boil. Thelongitudinally porous structure aids in the change of the liqueed gas toa vapor without itself .being inside the tank.

It is another object of thisV invention to produce ebullition ofliquefied petroleum gasesby inserting into the liquid an ebullatorcomprising an elongated member having a plurality of minute longitudinalcapillary passages extending from end to end. This may be a vegetablegrowth or it may be manufactured by some special process to imitate anyvegetable growth having longitudinal capillary passages extending fromend to end, the capillary passages being of such small cross-sectionalarea as compared with the length, so as to lower the pressure of theliquid at the central portions of the capillary passages to where it ismuch less than the pressure of the liquid at the ,open ends of thecapillary passages.

Some of the objects of the invention having 3 been stated, other objectswill appear as the de'- scription proceeds when taken in connection withthe accompanying drawings, in which:

Figure 1 is a side elevation, partly in section, I

Figure 5 is an enlarged longitudinal sectional view with lthe centralportion thereof broken away, and taken along the line 5-5 in Figure 4;

Figure v6 is a View of a portion of a piece of rattan, bamboo, orcellular wood in its natural state, from which the element for producingebullition is cut;

Figure 7 is an elevation of a liquefied petroleum gas tank partly insection, showing a slightly modified form of the invention;

Figure 8 is a transverse vertical sectional view taken along the line 88 in Figure 7,;

Figure 9 is an enlarged sectional view ofthe lower right-hand portion ofFigure '7;

Figure 10 is a sectional plan view taken along the line Ill-l0 inFigure'1;

Figure 11 is an elevation of another liquefied petroleum gas tank,illustrating another modied form of the invention;

Figure 12 is a transverse vertical sectional view taken along the lineI2I2 in Figure 11;

Figure 13 is an enlarged sectional detail view of the right-hand centralportion of Figure 12,

illustrating the manner of positioning the element for producing theebullition relative to the main liquid body in the tank;

Figure 14 isan enlarged sectional view-taken along the lines Ill- I4 inFigures 12 and 13;

Figure 15 is anisometric view of a spring clip 58 employed for conningthe ebullition element in position near the lower portion of the tank;Figure 16 is a view similar to Figure 13, lbut showing the ends of theebullition element cut in a special manner so that spacer elementstherebetween can be eliminated.

posed in housing 24. on the upper end of lpipe ls. The rising and :suingof the nquid ievei' s yactuates the float I8 which, in turn, actua-testhe pointer or indicator in the housing 2l tol cause it to rotate todiierent positions. When filling the above-described tank, a cap 2B isremoved from the upper portion of the ll pipe land. fuel is conductedinto the tank. At the saine time, the displaced vapor within the ta-nkis permitted to flow therefrom through a vent pipe 21. The details ofthe structure thus far describedcan be more completely understood byreferring to my 'copending patent application Serial No.

473,555, led January 25, 1943.

As heretofore explained, butane mixtures such as used for domestic fuelhave an initial theo- -retical boiling or evaporation point of approxi-Referring more particularly to the drawings,

, tank through a service pipe line I4, said pipe line extending upwardlythrough the interior of a ll pipe I5, and then to points of consumption.The service pipe line I4 is provided with a conventional excess flowvalve I6 and a shut-0E valve I 1.

The tank is also provided with a conventional gauge for indicating theliquid level within the tank, this gauge comprising a float I8, disposedon one end of a rod I9, said rod being secured intermediate its endsupon a shaft 20. The shaft 20 has a gear 2l xed thereon, which gearmeshes with another gear 22, said gear 22 being secured on the lower endof an indicating gauge shaft 23. Shaft 23 extends upwardly 'throughthell mately eighteen degrees Fahrenheit, and this is A* the point wheresuchl boiling barely starts when the temperature of the liquid isrising, or the point where the boiling stops when the temperature of theliquid is falling. Dueto the lack'of circulation or movement of the fueldisposed within the tank, this boiling to -any appreciable amount.actually ceases when the temperature fallsy to thirty-two or thirty-fivedegrees Fahrenheit. On account ofthe last-named temperature range be.

ing above some of the normal winter ground temperatures, the boilingceases in the tanks in cold weather and gives considerable trouble. Ofcourse, when the boiling of the fuel ceases, no vapor will be formed,and consequently, the service lline I 4 to the points of consumptioncannot supply any fuel. The above example 'relates to butane mixtures,however, the present invention is not limited to this particular gas,because the same principle might be employed in association with otherliquefied petroleum gases such as propane, and the like.

It is therefore evident that must be provided for producing ebullitionor the boiling o f mixtures such as butane at lower temperatures thanthirty-two to thirty-ve degrees Fahrenheit in order to make the .systemsmore operable during winter months.

In carrying out the present invention, it has been found that alongitudinally porous ebullition element such as a piece of rattan 30,or allied vegetable matter such as bamboo,'reeds,.cellular wood, or thelike may be employed to accomplish this purpose. Since these woodspossess similar characteristics, a description will be made inassociation with rattan in order to more speciflcally describe theoperation of the invention. Rattan has been defined yby CenturyDictionary as follows:

Rattan is any of the various climbing palms of the genus Calamus; any ofcertain low palms of the genus Rhaphis; also the tuft stems 'o'f suchpalms used for wicker work, canes, etc.; also a stock or switch of thismaterial. l

Rhaphis or Raphis is any of the palms of the genus Raphia, as oftropical Africa and America Botanically speaking, raphia is one of theminute needle-shaped crystals of calcium oxalate which occur in thecells of many plants.

Calamus is a reed or cane (these two terms are now obsolete to describeCalamus) The sweet iiag, Acorus calamus, or its aromatic root; any palmof the genus Calamus yielding rattan,

canes,'etc. (cf. rattan and Malacca cane); also the quill of a feather.The above-mentioned ebullition element of rate some simple means c asrouia of Madagascar which yields rama fiber.y

tan 30 is cut from betweenloints 3| of a `stall:

or limb of rattan 32 such as disclosed in Figure 6. The piece 30 may becut along any suitable spaced intervals such as long dotted lines 33provided the piece has the joints eliminated therefrom. Where a joint ispresent, the capillary passages in the rattan limb are very muchrestricted in size, if not entirely closed, but the capillary passages36 have substantially the same size throughout the entire length ofmaterial between the severing lines 33.

When a piece of rattan 30 is cut from the stalk 32, the natural skin 34is permitted to remain thereon to thereby seal the inside core portion35 of the rattan element. In other words, the natural skin 34 is of ahard non-porous nature, whereas the inside core portion 35 is of a`softer material. This intermediate core portion of element 30 has alarge number of longitudinal microscopic capillary passages 36 thereinextending from one end to the other of the element. The cross-sectionaldiameter of these passages will range from one-thousandth tothree-thousandths of an inch, depending upon the outside diameter of thepiece of rattan used. Such pieces of rattan as used usually range insize from threeeighths of an inch outside diameter by four inches longto three-fourths of an inch in outside diameter by twelve inches long,and, of course, these pieces are cut from between the joints and have acellular structure'comprising a series of natural longitudinal passageswhich continue from one end to the other. However, I desire it to beunderstood that any size of ebullator may be used.

On account of the small diameter of capillary passages 36 as contrastedwith relatively long length of the columns of liquid contained within,there is a pressure differential between the central portion of eachpassageway and the points where the liquefied petroleum gas enters thesepassageways. In other words, the pressure on the ends of-the liquidcolumn within the passageways might be two pounds to the square inch,and the pressure at the center of the column within the passageway mightbe only one and one-half pounds per square inch. This pressuredifferential is due, in part, to the capillary action or frictionexisting between the liquid and the wall of the passage, said capillaryaction creating a friction which tends to lower the pressure at thelongitudinal center of the liquid column.

This pressure differential is 'similar to that existing in pipe linesand is due to an exactly simiy to cause it to boil at a much lowertemperature lar action, and is a well known phenomenon.

For example, the longerv the pipe in a water main, the greater will bethe friction loss, which will reduce the effective water lhead at thepoint of distribution. Therefore, the pressure might be one hundredpounds per square inch where the water enters a main and only sixtypounds per square inch at the point of distribution, the loss in headresulting from friction. Each microscopic passageway 36 through therattan element 30 is, in effect, similar to such a pipe line and itfollows that the action therein is similar.

This difference in pressure existing within the microscopic column ofliquid disposed in the passages 36 enables boiling or evaporation of theliquid to start at the center of the columns before it will start at theends of the columns and in the surrounding liquid. It is a well knownfact that there is a very definite relationship besure `will be less atthe center of each passage 36, a condition is created where the liquidwill boil at this low pressure area before it will boil at thesurrounding points which are under a greater pressure.

Since rattan, bamboo, reeds, cellular wood; palm stems, and similarvegetable fiber in their natural state are usually of a porouscharacter, and usually have a lower specific gravity than liquefiedpetroleum gases il, these woods will oat unless they are weighted orotherwise prevented from floating. In the present form of the invention,each piece of rattan 30 has a pair of spaced metallic washers 39 securedtherearound, said washers serving to space the rattan from the bottom ofthe tank and also serving to weight the piece of rattan suiliciently toprevent it from oating.

As an example, consider a condition where liquefied butane gas isdisposed in tank I0, and where the boiling has ceased when thetemperature has dropped to thirty-four degrees Fahrenheit.Theoretically, this mixture should boil until a temperature of eighteendegrees Fahrenheit has been reached, but as heretofore stated, due tothe quiet state of the liquid, the boiling will cease at a much highertemperature. 'I'he purpose of this rattan element 30 is to cause aboiling of selected columns of liquefied gas which will, in turn,agitate the main body of the liquid than thirty-four degrees.

In the above example, when the temperature reaches thirty-four degreesand the boiling ceases, the vapor pressure in space I2 within the tankis zero pounds per squareinch or atmospheric pressure. The pressurewithin the liquidv body Il outside the rattan element 30 is thereforezero pounds per square inch or atmospheric pressure plus the depthpressure, and'this depth pressure in shallow tanks such as shown is sosmall that it may be disregarded. The pressure on the ends of thecolumns of liquid contained within each rattan passagel 36 is likewisezero pounds per square inch or atmospheric pressure, but the pressure atthe center of said column will be considerably less than the pressurethat prevails in the main body of the liquid outside 'the rattanelement. The liquid at the center of the column of the liquid withineach passage 36 will therefore start evaporation first to cause gasbubbles to be ejected from the ends of each of these pores, said bubblesrising after escaping from the passages through the main body of liquidIl and serving to agitate it to thereby cause the main body of liquid tostart evaporating or boiling at a point more vnearly to or at itsinitial boiling point, which in the present example, has been designatedas eighteen degrees Fahrenheit for butane mixtures.

Particular attention is called to the fact that the elements 30 whencomprised of rattan, bamtween pressure and boiling point.l In otherwords,

boo, reed, or the like have the natural skins 34 thereon. This naturalskin is very hard and nonporous and therefore seals the core portionagainst leakage.V The lpressure differential between the main body ofliquid H and the centers of passages 36 could not exist if radialleakage from the passages were permitted. Since -the inner core portion35 of the wood is of a softer material, it naturally follows that acertain amount of leakage would be permitted werel it not for thenatural non-porous skin .34 which encases the entire assembly oflongitudinal passages 36. 1t is therefore seen that the natural vskin 34sameeffect would be produced, however, the con struction of such anelement is costly, especially when vegetable material, such as bamboo,reed, l rattan, and the like are available at low cost.

It is therefore seen that the elements 30, regardless of the materialfrom whichthey are formed, clearly act as a catalytic agent. A catalyticagent is defined in chemistry as a material that aids chemical actionwithout itself being permanently changed. These catalytic agents arecommonly called ebullators.

In explaining the operation of the present invention, attention iscalled to the fact that vaporization is believed to mean the conversionof a substance into the gaseous form. If the change takes place slowlyfrom the surface of the liquid, it is called evaporation, but if theliquid is visibly agitated by rapid internal evaporation, the process iscalled ebullition or boiling. The rattan, bamboo, reed, cellular wood,or other elements 30 act at ebullators, and bring about the latterprocess.

Figures 7 to 10 inclusive show a slightly modi- Vfled form of theinvention in which the holding means for the' ebullition elements 36 isa built-in part of the storagetank in which the ebullition process isaugmented, said holding means comprising tubes or pipes, welded to thelower portion of the tank. Specically, the numeral 45 denotes a tankhaving a plurality of vertically disposed tubular pipes 46 extendingdownwardly from the lower portion thereof. There is also verticallydisposed end pipes 41 extending downwardly from the lower portion of thetank, said pipes 46 and 41 having their lower ends joined by alongitudinal header pipe 48. The pipes 46, 41, 48, as well as tank 45are buried in the earth 49.' A. piece of rattan, reed, bamboo, cellularwood, or similar ebullition element 30 if, inserted into each of lthevertically disposed pipa-s 46, .and each of these elements are held inposition within its respective pipe by any suitable means such as aspring clip 50. The end pipes 41 do not have an element 30 disposedtherein.

The ebullition action of the elements 30 within the pipes 46 causes theliquefied petroleum gas Il within the tank to be drawn downwardlythrough Vend pipes 41 and then horizontally .through header pipe 48,fromwhence it passes upwardly through the ebullition elements 30 withinpipes 46, and is finally ldischarged into the main bodyof liquid in thetank 45. The liquid in the passages 36 of the elements 30' is formedinto bubbles on account of the pressure differential, and these bubblespass upwardly through the main body of the liquefied petroleum gas Il tothus produce the desired ebullition such as described in the precedingform of the invention. i y

In the present form of the invention, the earth temperature will moredirectly affect the liquid within pipes 46, 41, and 48, as well asaffect the temperature of the elements 30 disposed within `perature incold weather will be much higher .than at shallower depths. Therefore,such a system will provide a means whereby the ground temperature can bemore favorably employed in cold weather to augment or agitate the mainbody of liquid Within the tank.

Such a system is designed to give a more violent bubbling and agitatingeiect to the main body of the liquid, thus achieving more completevaporization of the main body of liquid at lower temperatures than inthe conventional systems. Figures l1, l2, 13, 'and 14 show s`tillanother vmodified form of the invention in which the holdf ing means ofthe ebullition elements 30 are also a built-in portion of the tank, butof a dierent design. vIn this form, the numeral designates` a tankfor"liqueed petroleum gas Il, said tank having the ends .of a pluralityof spaced circular pipes 56 communicating therewith as at 51, Aplurality of ebullition elements 30 are loosely fitted within each pipel56, said elements being con-v ned .therein and prevented from floatinginto the main body of the liquid Il by any suitable means such ascircular spring clips 58.

I These spring clips 58 have inturned leg portions 58a, said inturnedportions serving to coniine the uppermost ebullition element 30 withinthe pipe 56, and also serving as projections which may be engaged by asuitable clamping .element when it is desired to contract the/clip toremove or insert the same in position within the pipe.

y Attention is called to the fact that suitable spacer members such ascompression springs 60 are provided between adjacent ebullition elements30 within pipes 56` These elements prevent the cut ends of the elementsfrom abutting and thus cutting off liquid contact. As an alternatemethod of preventing liquid contact from being cut. off at the ends, theebullition elements may be cut in .the manner shown in Figure 16. Inthis form of the invention, the ebullition element isl designated byreference character 62, and one end of each element is pointed or cut ona bias as at 62a, said bias portion being adapted to provided with asimilar manhole 55a which is employed for the same purpose. It is to beunderstood, however, that the employment of these the pipes 46 than inthe preceding form 'of theinmanholes is an optional feature, because theebullition elements 38, in many instances, may be inserted or removedthrough the stand .pipe attachment hole by employing a long handledgripping tool.

The circular pipes llili always communicate with the main body of liquidand will therefore remain lled so that the ebullition -action of theelements 3U will form vapor bubbles.

lThis ebullition action is greatly augmented by the heat of thesurrounding earth 48, and therefore, bubbles or Vaporization within theelements will be formed at a faster rate than in the iirst form of theinvention, wherein theebullition elements are deposited within the lowerportion of the main body of the liquid. The bubbles which are formedwithin the circular pipes 56 are permitted to escape as at 5 1 into themain body of the estense liquid l l, and thus agitate this liquefiedpetroleum gas to cause boiling to take place at e lower tem pereturethan it would otherwise boil.

In the drawings and specification, there has been set forth a, preferredembodiment of the invention and although specific terms are employed,they are used in a. generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being dened in theclaims.

ll claim:

v 1. The method of promoting veporizetion in e confined body ofliquefied fuel, which includes submerging in said body one,or more rodseach comprising e. jointfree portion of ratteniike plant metter andhaving the capillary passages et the end of the rod open for penetrationby the lionen ed fuel end the portions between the ends pro= tected bythe neturel skin of the plant.

2. The method of promoting vaporizetion in e. s

confined body of liqueed fuel, which consists in drawing fuel vaporsfrom seid body and et the same time exposing the iuel to' the capillaryection of the natural plant passages of one or more submerged rods, eachcomprising a jointlree por tion of e, steil; of rettenlilse plant metterand having the portions between the ends of the rod protected by thenaturel slain of the nient., v

lil

nismsnnuoes einen The following references are of record in the NumberName Date l.,917,154 Porter July 4, 1933 1,931,268 ,Philipp Oct. l?,i933 2,121,6'l5 White June 2l, i938 1,298,821 Nordell Dec. i9, 1.9i@i,23,079 Andrews Sept. l5, i931 1,929,511 Mulkey Oct, i0, 1933 2,1%,367Mead Feb. 13, 19450 2,332,349 Schulz Ooi; 19, i943 2,255,584 Hubackerl.- Sept. 9, 194i.

